1. Matrix Encryption Algorithm for MP4 Audio and Video
Sandeep Chandrashekaregowda
April 15, 2014
UCCS
Master’s Project Report
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2. Agenda Introduction / Motivation Background Design Analysis
Implementation
Testing
Conclusion / Future Work
References
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3. Introduction
Communication is important part in life with confidentiality and integrity
Multimedia has become one of the most realistic means of communication
Multimedia is the media that uses multiple forms of information content and information processing
Text, audio, graphics, animation, video
This project presents Matrix Encryption Algorithm frames in multimedia, render the file playable
Text: Text and symbols are very important for communication in any medium. With the recent explosion of the Internet and World Wide Web, text has become more the important than ever. Web is HTML (Hypertext Markup language) originally designed to display simple text documents on computer screens, with occasional graphic images.
Audio: Sound is perhaps the most element of multimedia. It can provide the listening pleasure of music, the startling accent of special effects or the ambience of a mood-setting background.
Images: Images whether represented analog or digital plays a vital role in a multimedia. It is expressed in the form of still picture, painting or a photograph taken through a digital camera.
Video: Digital video has supplanted analog video as the method of choice for making video for multimedia use. Video in multimedia are used to portray real time moving pictures in a multimedia project.
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4. Introduction
Each such still image is referred to as a frame in a video
I-frame : I-frames are pictures coded without reference to any pictures except themselves [2]
P-frame : P-frame holds the changes in the image from the previous frame [2]
B-frame : specify the content by using differences between the current and both preceding and following frames. [2]
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5. Introduction Frames Structure [2]: Sandeep - Master's Project Report
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6. Motivation Three major classification of video encryption [1]
Fully layered Encryption
Permutation based Encryption
Selective Encryption
Selective encryption algorithms are not encrypting each and every byte of video data
Selective algorithm encrypts with video frames[1]
Sharing requires communication through insecure channel
Fully layered Encryption: In this class, whole content of video is first compressed and then encrypted using standard tradition algorithms like DES, RSA, IDEA, AES etc. This technique is not suitable in real time video applications due to heavy computation and slow speed.
Permutation based Encryption: The video encryption algorithms in this class mainly use different permutation algorithms to scramble or encrypt the video contents. It is
not necessary to scramble each and every byte. Some algorithms use permutation list as secret key to encrypt video contents.
Pure Permutation : Pure permutation algorithm is simply scrambles bytes within a frame of MPEG stream by permutation.
Zig-Zag Permutation: Instead of mapping the 8X8 block to 1X64 vector in “Zig-Zag” order
Selective Encryption: The algorithms in this class selectively encrypt the bytes within video frames. As these algorithms are not encrypting each and every byte of video data, it reduces computational complexity.
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7. Related Work SECMPEG by Meyer and Gadegast [Meyer,1995]
Secure MPEG: Four levels of security
Sequence of encryption by Encryption Standard (DES) symmetric key cryptosystem
[Qiao, 1997] Video Encryption Algorithm by Qiao and Nahrstedt
Dividing the input video stream into chunks
chunk is 1/8 or 1/16 of the I-frame
Uses symmetric key algorithm standard.
Video Encryption Methods by Alattar, Al-Regib and Al-Semari [Alattar, 1999]
selective video encryption based on DES cryptosystem
Encryption is applied to the data associated with every nth I- macroblock.
Macro block Cipher is not suitable for streaming video as they cannot determine which frame is currently being played back
First Layer: SECMPEG encrypts the headers from the sequence layer to the slice layer
Second Layer: I-blocks are additionally encrypted
Third Layer: SECMPEG encrypts all I-frames and all I-blocks
Forth Layer: SECMPEG encrypts the whole MPEG-1 sequence.
hash message authentication code (HMAC) is a specific construction for calculating a message authentication code (MAC) involving a cryptographic hash function in combination with a secret cryptographic key.
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8. Related Work
Encryption Algorithms for Videos by Cheng and Li [Cheng 2000]
Partial encryption schemes for still images introduced by Cheng and Li are also further extended to the videos
Quad tree compression is more efficient at low bitrates and brute force attack is practical for low information images [25]
Partial encryption algorithms are designed to disguise the intraframes ,motion vectors, and the residual error code of the given video sequences
In video compression a motion vector is the key element in the motion estimation process. It is used to represent a macroblock in a picture based on the position of this macroblock [25]
Quadtree : A quadtree is a tree data structure in which each internal node has exactly four children[21]
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9. Related Work
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10. Encryption and Decryption Process
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11. Select frames to encrypt
All I frames are encrypted. Therefore no original content in those frames will be leaked.
The macroblocks in P or B frame which are not encrypted by the matrix encryption algorithm are those whose content are the same as correspond macroblock in I frame. Since the correspond macroblock in I frame are encrypted, their original content can be derived.
Macroblocks of those P or B frames with differentiated content are encrypted.
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12. Matrix Encryption Algorithm Design
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13. Matrix Encryption Algorithm Design
Initial Round
Divide the stream in frames to 16 bytes of sub-frames; consider it as a 4x4 matrix. Each sub-frame is encrypted separately Decryption operation
Rounds:
Operate on the part of matrix: Divide the matrix as 2x2 matrix. Perform Xor operation on 1st part of the matrix with its next one
Operate with Key: Perform Xor operation on the 4x4 matrix with key of 16 bytes
Shift cells: shift the divided matrix cell values clockwise
Final Round
Append the encrypted sub-frames
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14. Matrix Encryption Algorithm Design
Initial Round
Step 1. Create matrix
Step 2. xor X00(00,01, 10, 11) with X01(02, 03, 12, 13) respectively which updates only 1/4th of matrix.
Step 3. Rotate X00-> X01-> X11-> X10-> X01
Step 4. Add Key
Step 5. Repeat step 2, 3, 4 for 3 more times. (Means all the 4 parts of matrix are updated).
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15. Matrix Encryption Algorithm Design
Second Round
Step 1: The MES uses16 bytes key, which will be XORed with the resultant of the above step matrix just like AES
Step 2: Second step will actually shuffles the bytes in the matrix
Third Round
Step 1: Unlike AES, which will shifts values within row. This algorithm will rotate the value position.
Step 2. The values changes row-wise as well as column- wise
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16. Security Analysis
Macroblocks of those P or B frames with differentiated content are encrypted.
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17. Security Analysis Secured Frames
All I frames are encrypted. Therefore no original content in those frames will be leaked.
The macroblocks in P or B frame which are not encrypted by the matrix encryption algorithm are those whose content are the same as correspond macroblock in I frame. Since the correspond macroblock in I frame are encrypted, their original content can be derived.
The rest of the macroblock in P or B frame are encrypted.
Therefore all P or B frame content are encrypted.
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18. Implementation
MES is implemented for this project to validate the designed algorithm, evaluate performance, and provide a tool that could be used for future applications.
Built in the C #language
Microsoft Visual C# 2010 Ultimate
Windows 8.1
The implementation includes reading a MP4 file and breaking the file into metadata, video frames and audio frame
Encryption will be performed only on the frames, which is decided based on the selection of encryption mode, video only, audio only or both.
Creation of key file with random key, generated in the program
Breaking the frame into parts of 64 bits.
Each part is then converted to matrix to apply Matrix Encryption Algorithm on it.
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19. Implementation
Encrypted matrix is again serialized to 64 bits to create the encrypted MP4 file
The person encrypts the video with the Matrix Encryption Algorithm.
The person can decrypt the video with key along with MES decryption technique.
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20. Performance comparison
Sizes of MP4 files and audio/video samples in test data set
File Name
File Size
# of Audio samples
# of Video samples
21.mp4
21 MB
15357
8903
40.mp4
40 MB
9204
5345
59.4.mp4
59.4 MB
49365
34354
82.mp4
82 MB
47221
27412
107.mp4
107 MB
25054
14544
215.mp4
215 MB
49552
28765
719.mp4
719 MB
125623
58398
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21. Performance comparison
MES and AES Algorithm encryption Performance
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22. Performance comparison
MES and AES Algorithm decryption Performance
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23. Performance comparison
Matrix Encryption Algorithm performs slightly better than Advanced Encryption Standard Algorithm when we go on increasing the size of the file.
AES algorithm performs better encryption for file sizes up to 59.4 megabytes
MES algorithm bumps up when the encryption process for files greater than 59.4 megabytes.
Decryption process takes slightly longer when compared to encryption process
Advantage of skip frames which does not need to encrypted.
The type of files that can be benefited from using MES are the files whose video content is not changing so that the macroblocks in the P and B frames does not have to be encrypted/decrypted.
Sandeep - Master's Project Report
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24. Lessons Learned Confronted and unlocked implementation challenges
Overhead of selecting frames
Key management
Challenging to study the file format and catch the exact frame data to perform the encryption operation
Algorithm design
Implementing data files to matrix
Adding key file to output transparently
Testing
Getting the MP4 files to test the algorithm
Hardware crashes for larger files
Analyzing the implementation on security
Analyzed the key size with several other papers to generate transparent key
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25. Conclusion
The Matrix Algorithm scheme provides a framework for efficient encryption and decryption in the multimedia environment
Matrix Encryption Algorithm it is suited for protecting multimedia files with files whose video content is not changing
Faster means of data protection with confidentiality and integrity
Transparent encryption and decryption
Easy user interface without much overhaul
Additional information available:
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26. Future Work
To extend to mobile devices which in turn based on the cloud :
A good application can be developed using for the algorithm using VBE language to encrypt the data without using internet and transferring the data in a secure manner along with key when internet comes in contact
Can be extended to sports authorities so as they tend use mobile devices without internet and send the results in secured way.
Security Proof
A conceptual analysis of cryptographic strength is presented
Future work can prove of the security based on real time testing on SED’s.
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27. Questions?
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28. References
Qiao, Lintian, and Klara Nahrstedt. "A new algorithm for MPEG video encryption." Proc. of First International Conference on Imaging Science System and Technology
Liu, Fuwen, and Hartmut Koenig. "A survey of video encryption algorithms."computers & security 29.1 (2010): 3-15.
Lui, Oi-Yan, Ching-Hung Yuen, and Kwok-Wo Wong. "Chaos- Based selective encryption for AVS video coding standard." Advances in Multimedia Information Processing–PCM Springer Berlin Heidelberg,
Lim, Youngkwon, et al. "MMT: An Emerging MPEG Standard for Multimedia Delivery over the Internet." MultiMedia, IEEE (2013):
QuickTime API Reference, , Apple Computer, Inc. © Apple Computer, Inc.
MP4 Wiki
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29. References
Bleichenbacher, Daniel. "Chosen ciphertext attacks against protocols based on the RSA encryption standard PKCS# 1." Advances in Cryptology—CRYPTO'98. Springer Berlin Heidelberg, 1998.
Brumley, David, and Dan Boneh. "Remote timing attacks are practical."Computer Networks 48.5 (2005):
Canvel, Brice, et al. "Password interception in a SSL/TLS channel." Advances in Cryptology-CRYPTO Springer Berlin Heidelberg,
Albrecht, Martin R., Kenneth G. Paterson, and G. Watson. "Plaintext recovery attacks against SSH." Security and Privacy, th IEEE Symposium on. IEEE, 2009.
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30. References
Ravishankar, K. C., and M. G. Venkateshmurthy. "Region based selective image encryption." Computing & Informatics, ICOCI'06. International Conference on. IEEE, 2006.
Multimedia Security Handbook by Borko Furht and Darko Kirovski, published by CRC Press LLC in December 2004
Albrecht, Martin R., Kenneth G. Paterson, and G. Watson. "Plaintext recovery attacks against SSH." Security and Privacy, th IEEE Symposium on. IEEE, 2009.
Meyer, Jürgen, and Frank Gadegast. "Security mechanisms for multimedia data with the example MPEG-1 video." Project Description of SECMPEG, Technical University of Berlin, Germany (1995).
Alattar, Adnan M., Ghassan I. Al-Regib, and Saud A. Al-Semari. "Improved selective encryption techniques for secure transmission of MPEG video bit-streams." Image Processing, ICIP 99. Proceedings International Conference on. Vol. 4. IEEE, 1999.
Cheng, Howard, and Xiaobo Li. "Partial encryption of compressed images and videos." Signal Processing, IEEE Transactions on 48.8 (2000):
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31. References
Simmons, Gustavus J. "Symmetric and asymmetric encryption." ACM Computing Surveys (CSUR) 11.4 (1979):
But, Jason. Limitations of existing MPEG-1 ciphers for streaming video. Vol Technical Report CAIA, 2004.
Massoudi, Ayoub, et al. "Overview on selective encryption of image and video: challenges and perspectives." EURASIP Journal on Information Security 2008 (2008): 5.
weekly/blog/bid/63272/How-to-Test-for-Brute-force-Vulnerabilities
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